Exposure to bright light has been demonstrated to be effective in multiple studies of bright-light therapy for seasonal and non-seasonal depression. These studies have also defined an optimal dose of light as a function of intensity and time. Light has an effect on hormones and neurotransmitters (e.g., melatonin and serotonin), which are involved in the regulation of mood, energy, and appetite.
Studies have also demonstrated that bright light can reduce insomnia associated with circadian rhythm difficulties. Light therapy may also be helpful in treating depression during pregnancy, dementia in the elderly, bulimia nervosa, severe premenstrual syndrome, attention deficit hyperactivity disorder, and bipolar disorder.
Based on these findings, psychiatrists have conducted studies and prescribed the use of artificial light boxes, requiring patients to sit in one place, indoors, and close to the light source to provide controlled means of dosing the light to the patient. Despite the known benefits, bright-light therapy is not widely prescribed by doctors, according to a recent New York Times article (R. Rabin, “A Portable Glow to Help Melt Those Winter Blues,” New York Times, 14 Nov. 2011).                Why, then, do so few doctors prescribe bright-light therapy? Some say their patients don't have the patience to sit in front of a light for 30 to 45 minutes every morning. Moreover, “doctors are just more comfortable prescribing medication, because that's what they do for everything,” Dr. [Alfred] Lewy [professor of psychiatry at Oregon Health and Science University] said.Id. Accordingly, depression therapy currently remains focused, in large part, on medication with some use of light-box therapy.        